Rock drilling rig include a carrier and at least one boom unit having a drilling unit. Rock drilling rigs and drilling units therein may be used, for example, in tunnelling or in other rock breaking operations in mines or excavating sites. A drilling unit typically has at least one rock drilling machine with a tool that is formed of one or more interconnected drill rods or drill pipes. At a distal end of the tool there is a drill bit. During drilling the drill bits become worn or may be broken and must therefore be replaced. It is also possible that a beginning of a hole, i.e. a reamer hole, is drilled with a drill bit having a smaller diameter and the drilling of the hole is thereafter continued with a drill bit having a larger diameter. In that case the drill bits must be interchanged at some point of the drilling.
Changing of the drill bits is typically carried out manually by an operator of the rock drilling rig. The changing of the drill bits manually requires the operator to leave a cabin or canopy of the rock drilling rig and possibly enter into an area with unsupported or unreinforced roof of a tunnel, which may be unsafe. The changing of the drill bits may also involve cumbersome working positions and lifting or otherwise handling of possibly heavy items.